Clean up code

day9/src/main.rs

@@ -1,86 +1,48 @@
-use std::{cmp::Ordering, fmt::Display};
-
-#[derive(Debug, Clone, Eq, PartialEq)]
-struct Space {
-    id: Option<usize>,
-}
-
-impl Display for Space {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(
-            f,
-            "{}",
-            if let Some(i) = self.id {
-                i.to_string()
-            } else {
-                ".".to_string()
-            }
-        )
-    }
-}
-
-impl PartialOrd for Space {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
-impl Ord for Space {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        if self.id.is_none() {
-            return Ordering::Less;
-        }
-        if other.id.is_none() {
-            return Ordering::Greater;
-        }
-        self.id.unwrap().cmp(&other.id.unwrap())
-    }
-}
-
-fn parse(input: &str) -> Vec<Space> {
+fn parse(input: &str) -> Vec<isize> {
     input
         .chars()
         .enumerate()
         .filter(|(_, c)| c.is_ascii_digit())
         .flat_map(|(c_idx, c)| {
-            (0..c.to_digit(10).unwrap()).map(move |_| Space {
-                id: if c_idx % 2 == 0 {
-                    Some(c_idx / 2)
+            (0..c.to_digit(10).unwrap()).map(move |_| {
+                if c_idx % 2 == 0 {
+                    c_idx as isize / 2
                 } else {
-                    None
-                },
+                    -1
+                }
             })
         })
         .collect()
 }
 
-fn checksum(filesystem: &[Space]) -> usize {
+fn checksum(filesystem: &[isize]) -> usize {
     filesystem
         .iter()
         .enumerate()
-        .map(|(c_idx, c)| if let Some(v) = c.id { c_idx * v } else { 0 })
+        .map(|(c_idx, c)| if c >= &0 { c_idx * *c as usize } else { 0 })
         .sum()
 }
 
-fn part1(filesystem: &mut [Space]) -> usize {
+fn part1(filesystem: &mut [isize]) -> usize {
     for space_idx in 0..filesystem.len() {
-        if filesystem[space_idx].id.is_none() {
+        if filesystem[space_idx] >= 0 {
+            continue;
+        }
         let last = filesystem
             .iter()
             .enumerate()
             .rev()
-                .find(|(_, n)| n.id.is_some())
+            .find(|(_, n)| n >= &&0)
             .unwrap();
         if last.0 < space_idx {
             break;
         }
         filesystem.swap(space_idx, last.0);
-        };
     }
     checksum(filesystem)
 }
 
-fn get_chunk_size(filesystem: &[Space], idx: usize) -> usize {
+fn get_chunk_size(filesystem: &[isize], idx: usize) -> usize {
     let mut chunk_size = 0;
     while idx + chunk_size < filesystem.len() && filesystem[idx + chunk_size] == filesystem[idx] {
         chunk_size += 1;
@@ -88,17 +50,17 @@ fn get_chunk_size(filesystem: &[Space], idx: usize) -> usize {
     chunk_size
 }
 
-fn part2(filesystem: &mut [Space]) -> usize {
-    for move_id in (0..=filesystem.iter().max().unwrap().id.unwrap()).rev() {
+fn part2(filesystem: &mut [isize]) -> usize {
+    for move_id in (0..=*filesystem.iter().max().unwrap()).rev() {
         let move_idx = filesystem
             .iter()
             .enumerate()
-            .find(|(_, c)| c.id.unwrap_or(move_id + 1) == move_id)
+            .find(|(_, c)| c == &&move_id)
             .unwrap()
             .0;
         let move_chunk_size = get_chunk_size(filesystem, move_idx);
         for free_idx in 0..move_idx {
-            if filesystem[free_idx].id.is_some() {
+            if filesystem[free_idx] >= 0 {
                 continue;
             }
             if get_chunk_size(filesystem, free_idx) >= move_chunk_size {